1. Field of the Invention
The present invention relates to a supporting structure for a rotor, wherein the rotor shaft and the supporting member of the supporting structure have the smallest contact area while providing stable and non-skew rotation for the rotor.
2. Description of the Related Art
FIGS. 1 and 2 of the drawings illustrate a conventional motor structure that comprises a metal axle tube 90, a stator 91 mounted around the axle tube 90, a circuit board 92, and a balance plate 98. An oily bearing 93 is tightly engaged in the axle tube 90 for rotatably supporting a shaft 95 of a rotor 94. A distal end of the shaft 95 is rotatably supported by a support member 96. The rotor 94 rotates stably by means of mutual attraction between a permanent magnet 97 on the rotor 94 and the balance plate 98.
In such a conventional motor, the rotor 94 could not rotate smoothly, as the lubricating oil in the oily bearing 93 leaks after the oily bearing 93 has been used for a period of time. In addition, the shaft 95 of the rotor 94 and the oily bearing 93 have a relatively large contact area therebetween. As a result, a relatively large friction exists and a larger noise is generated during rotation of the rotor 94. Furthermore, the cost for processing and manufacturing such a conventional motor is high.
It is the primary object of the present invention to provide a supporting structure for a rotor. The supporting structure can be manufactured conveniently. In addition, the shaft of the rotor and the supporting member for the shaft have a relatively smaller contact area therebetween.
In accordance with the present invention, a supporting structure is provided for the rotor and includes a metal axle tube, a holding member securely mounted in the axle tube, a supporting member securely mounted in the axle tube and including a supporting portion, and a fixing member securely mounted in the axle tube and including an opening. The holding member includes a hole and an inner flange is formed on an inner periphery defining the hole.
A shaft is provided to a center of the rotor and includes an engaging groove. The shaft is extended through the hole of the holding member and the opening of the fixing member with an end face of a distal end of the shaft rotatably resting on the supporting portion of the support member and with the fixing member engaging with the engaging groove of the shaft, whereby the shaft and the inner flange of the holding member have a slight contact therebetween.
Other objects, specific advantages, and novel features of the invention will become more apparent from the following detailed description and preferable embodiments when taken in conjunction with the accompanying drawings.